Telephone-exchange system.



E. E. CLEMENT- TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED 111111.27, 190's.

1,107,1 34. Patented Aug. 11, 1914.

2 SHEETS-SHEET l.

OLEM HN'I'.

TELEPHONE EXPHANGE SYSTEM.

APPLICATION 11'LED.\[AR.?'7,100i

Patented Aug. 11, 1914.

2 SHEETS- SHEBT Z.

HIHIIH UNITED STATES PATENT criterion.-

nnwsnn r..- cLEMENT, or WASHINGTON, DISTRICT or coLuJs/mni, assrcNon, BY.

MESNE' ASSIGNMENTS, TO FREDERICK C. STEVENS, 0E ATTICA; NEW YORK.

; TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

PatentedAug, 11, 1914.

Application filed March 27, 1905. Serial No. 252,307.

have invented certain new and useful Improvements in. Telephone-Exchange Systems, of which the following, is a specifica tion, reference being had therein to the accompanying drawing. I

My invention relates to telephone exchange systems, and has for its object the production of improved means of ringing or signaling a wanted subscriber.

. f Stated in a word the invention is a scheme forautomatic ringing, but it is an improvenient over the ordinary automatic, 'in 'that the calling subscriber may have control of the ringing key after the operator has once rung, and may repeat the ring as often as he desires until the wanted subscriber answers after which he cannot ring, but at all times can call the operator, or make a recall In one embodiment of the invention I give the control of the ringing after the operator has,,set the connection up, to a mechanical -device which if not impeded will ring at periodical and predetermined intervals. After the called subscriber has answered, however, neither this machine nor the calling subscriber, orfor that matter the operator, can afi'ect the ringing relay.

My invention is fully illustrated in the accompanying drawings, wherein Figure l is a, diagram showing the scheme applied to a two wire common battery cord circuit, the line jacks being three-wire; Fig.

2 is a diagram showing the invention applied to party line selective ringing; and Fig. 3 is a diagram similar to Fig. 1 showing modified means for controlling the battery supply.

In the drawings, and referring first to Fig. 1, A and A are two subscribers stations, each equipped with the usual telephone outfit and ringer, adapted to work in a common battery'system. Each line 1-2 or 34 terminates in a jack at central, J or J to the thimble of which the cut-ofi'relay N is connected and to ground. The cord circuit includes the plugsP and P, connected by conductors 56, 7-8, separated by condensers as customary- In a bridge 911 14-15 across the answering end of the cord are connected the relays S, S and the main battery B. In a similar bridge '10-l214: across the calling end of the cord are con nected the relays 'S, S and the main bat I jacks; and relays S and S close the circuitsof the supervisory lamps s and 's when they are deengerized, being'furnished with back contacts for the purpose; As the battery B is connected by its free pole to the sleeve side of the cord and so to line, the cut-0E relay N gets current when any plug goes in, being then in series with the relay S or S as the case may be.

' All the above is old and notdescribed as a part of my invention except as it must be included for completeness in operation. The circuit I have set forth and illustrated, moreover, may be varied at will without affecting myimprovements, which I will now point out particularly.

' From the tip and sleeve of the plug P the respective strands pass as 'usual to a ringing key, but instead of a mechanical key I show a magnetic key or relay, K. The armatures of this relay, is and k normally complete the cord and disconnect the generator circuit. The magnet of this relay has its winding included in a branch taken 011 from the back contact of the called subscribers supervisory relay, S, the circuit 1 ein from said bac contact by wire 19to the ack contact of a disabling relay S, thence by wire 190 to relay K, and thence to ground by one of three paths. The first path is through the operators ringing butt-on K", the second through the wire 22 and switch m to the constantly revolving commutator KVwhich first puts ground on the wire 22 for three seconds and then takes it off for the same length of time, and the third through the wire 22 to-switch m and by wire 20 to the back contact of the calling Supervisor relay S. It should 'be stated herethat'tlie relay-K is made very sluggish, so that it takes an appreciable length of time to pull in its armatures. This may be attained by either putting a copper ring on its poles, by giving wide air gap and a poor magnetic circuit, orgby vother means well known to thoseiskilled in'the art. The function of the relay S is to. close circuit from the battery; wire 15 to the wire 17, so as to Supply current to the contact of the, relay is, which thereafter deter.- mines whether the lamp 8' shall receive current or not. 'When the called subscriber ing without current and dark throughout the conneetionl When the called subscriber answers it lsnecessary'to provide against continued ringing, hence I take the tap 19 ofl in parallel with the lamp branch 18 and so to the relay K. I

In the answering end of the cord the relays S and S correspond in their functions to S and S, and since it is my desire to have the calling subscriber control ringing after the first ring, I take the wire to ground through back contacts of the relay S, which are separated when the relay .is energized;

It might happen that the called subscriber would hang up first, and in fact in relay K is made sluggish. This is'not es most cases this does happen. In such case if the calling subscriber tried to make a recall by attracting the attention of the operfator through flashings of the supervisorylamp 8, he would ring again the subscriber with whom he had previously conversed. It is to cure this that I introduce the selflocking relay S. I have stated that the sential so long as the relay S" is provided,

althoughit is preferably so in order to en-' able the calling subscriber to give a special signal to the operator. even before the called subscriber answers. The relay S is grounded on one side, and is connected to afront energizes the relay S which is as long as the calling plug P remains'in the jack J After the called subscriber has answered, and his supervisory relay S has once pulled up, it-is therefore impossible to .energizethe ringing relay K again withoutwithdrawing the plug P, to permit the magnets S and S to release, and then reinserting it. i

In Fig. 2, I have shown a cord circuit, or rath'erthe callingportion thereof, suitable for use with party lines, showing the applicability of my invention thereto.v Here the relay K has the same connections as '1n Fig. 1, and the cord circuit is the same,

so I have omitted these. Whereas in Fig.

1,"however, I have shown the generator cirwait '23 containing generator G, bridged across the tip and sleeve of the plug through the armatures It and in ringing, in Fig.

2 I have shown a pair of bus-wires 23 and 230, extending from the ringing contacts of the relayK through four selective keys K Ka -K and K each of which is adapted to connect a particular generator in a suitable manner to ring someone of four stations on a party-line. There are numbers of ways in which this can be done, but I have chosen to indicate four generators G G G and G, connected respectively scribed is as follows: Assuming that subscriber A desires connection with subscriber A, the former removes his telephone from the hook and thereupon current flowing in his line 1-2 will energize the relay M and light the linelamp. The operator perceiving the signal inserts the plug P in the jack J, whereupon current flows from battery B through wire 1.5, relay S and wire 11, conductor 7 plug and jack to the cut off relay N, which pulls up and removes the line relay M from the circuit. Current also flows over the path thus traced and out over the line wire 2 through the 'subscribers station, back by line wire 1, conductor 5, wire 9, relay S and wire 14 to ground. This supplies talking current, and by energizing the relay S disconnects the battery wire 13 from the lamp 8 and the ground wire 1+1 from the branch wire 20. Having ascertained the number wanted and tested the line jack thereof, the operator inserts the plug I The first effect of this is to permit current to flow from battery B by wire 15 through the relay S and cord conductor 8 to the cut off relay N of the called line, which removes the line relay and signal therefrom. At-the same time relay S puts current on wire 17 and the armature 8 I should here state that I have not considered it necessary to show the operators listening key, this being of any well-known or desired type. After inserting the plug, the operator may ring by pressing the button K", which closes the following circuit: B, 15, 17, 18, 19, s, 190, K, 21, K and ground back to battery. Relay K thereupon pulls in its armatures, disconnects the plug P from the cord conductors 6 and 8, and connects it to the generator circuit 23 and on the sleeve side through coil I to the battery. Upon releasing the key K" the relay K lets go. and re-completes the t-alkin circuit, and thereafter if the called subscriber does not immediately answer, further ringing may be done in any one of three ways, viz., by the operator ag'ain depressing key K"; by the subscriber moving keyentirely, simply inserting the plug P a his switch. hook up and down somewhat slowly at the calling station A; or by the automatic commutator controller K Strictly speaking, these arenot alternatives, nor are they intended to be used all atoms. The operatorfs key K I have shown perma nently connected, as the operator should always have control if she desires to exercise it; but the other two operating means I have shown provided with switches m, m, whereby either or both may be disconnected, in the latter case the operator retaining sole control, as at present. 7

The commutator K groundsthe magnet K for a specific periodof any/desired duratiop, and then takes 011' the ground for a certain period, thus intermittently exciting the relay K and ringing the subscriber A at intervals. This ringing means may well be employed during rush hours, and the opera tor may then abandon the use of her manual and leaving the commutator to do the rest. This would be most desirable during the busy hour in the business district, where calls are answered with promptness, and the call-t ing subscriber does not wish to do anything himself, finding even that waiting without working is too much of'a ta-x on his patience. The switch m being opened, and the switch m closed, control of the ringing is now given to the calling subscriber. All subscribers are informed that after theyhavefinitiated a call and a connection, they can actually ring up the party wanted by moving the hook up and down somewhat slowly. The makes and breaks thus produced in the circuit 12 cause the relay S to become intermittently' energized, making and breaking the contacts connected to the lamp 8 and to the ringing wire 20, by the following circuits: for the lamp, B, 15, 13,-s and ground; for ringing, B, 15, 17, 19-, 8 ,190, K, 22,20 and ground.- If the oscillations are very rapid the subscriber will as rapidly flash the lamp 8, even if relay K is made quick, the operator then understanding that the subscriber wants her alone. Y

- On a recall, after the conversation has been finished and before plug P has been re moved, the lamp canagain be flashed, asv usual, without ringing. No matter what the means of control for the ringing, when sub scriber A answers by taking down his receiver he completes a path for current from the main battery B over his line through the supervisory relay S. When this relay pulls "up it cuts off the wire 19 aswell as the lamp ,9 from the battery wire 17, and-connects the latter through Wire 16 to the relay S, which in turn pulls, up, and while armature s breaks the wire connection 19-190, the armature s closes from 17 direct to the winding of S, making the relay self-locking, remov ing it from the further control of relay S,

and placing it under the control of S that is locking it up until the plug P is actually withdrawn for a greater or less period from the jack J The circuit of relay K being thus permanently broken when the called subscriber answers, the hanging up of his receiver may be followed by an immediate re call due to the calling subscriber moving his switch hook up and down, to flash the lamp 8, without ringing. The operator perceiving this lamp flash and the other lamp 8 to burn steadily, will at once withdraw theplug P and come in on her listening key ready to I make another connection without withdrawing the plug P. As soon as the plug P is pulled, the relay S loses current, lets go its armature, and the self-locking relay S also then lets go, even though the armature of S is back. The circuit of magnet K is thus restored, and the magnet S 1s again placed under the control of relay S. v j

Referring to Fig. 2, the operation in ringin a subscriber on a pasty-line is the same as that described in the foregoing, except that the operator after inserting the plug P depresses one of the keys K", K K or K corresponding to thestation'wanted. This connects "a generator to give suitable current to ring the bell at that station. Each of these keys remains down when depressed, leaving its generator on the terminals 23230. For repeated ringing therefore the same generator will again be connected each time unless another key is depressed. This saves the operator even in nianual r1 ag ifng the trouble of finding the key used beore.

I have described my invention as applied to atwo wire cord of the so-called four-relay type. Obviously however, it is not limited to that type or to two wires. The prime requisites upon which it depends are the supervisory relays S, S, which are found in almost every system. A secondary requisite is found in the relays S S or their equivalent. These relays merely cut off battery from the lamps in the cord when the latter is idle; and they may be and frequently are replaced by plug seat switches, by third conductors in the cord and third contacts on the plugs cooperating with the sleeves of the jacks, or the like. In Fig. 3 herewith I have illustrated the first of these modifications. In this figure the general circuit is the same as that of Fig. 1, but the wire 17 is shown removed from control of the relay S and connected to the battery wire 15 through aplug seat switch P of the type illustrated and described in U. S. Letters Patent No. 507,983, November 7, 1893, to O A. Bell.

This is so arranged that when a plug P is shown and; describedin U.;S. 'Letters Patent. No,564,328, July 24, 1896, to W. W. Dean:

I 'havedescri'bed my invention as applied to subscribers lines direct, but it is particu-- larly applicable to trunk line ringing.

Having thus described. my invention what I claim and, desire to secure by Letters.

, Patent is:

' 1. In a telephone exchange system, a call-' ing and acalled subscribers line, with an operators cord-circuit to interconnect them;

a ringing generator and means to connect it to the called linef'only, magnetic means.

for actuatmgsaid'connectmg means adapted to-b'e controlled .by the calling subscriber, and other means independent. thereof for disabling the connecting means, controlled ,by the calledgsubscriber, substantially as described; t

- 2. In aitelephone exchange system, a calling and a called line, and a cord-circuit for interconnecting them comprising an answer- 2 ing and a callmg plug and cord conductors inductively divided; a supervisory relay con-.

'n'ected with the answerin' end of the cord I to be "cont-rolled by, the ca ling subscriber, a

second fsupervisory relay connectedwith the 3Q,mallingend of the cord and controllable by theealled subscriber-,a ringing relay associatjedswith the calling plug and a sultable 1 I source/or ,sources'of'ei'lrrent adapted to be connectedthereby, means controlled by the ;;answering supervisory relay 7 as determined byjtlr'e calling subscriber, foractuatlng the ringing relay, and means controlled by the calling supervisory relay as determined by thecalled Esubscriher for permitting or pre AflgjjVGIltlIlQithG actuation of said ringing relay,

substantially asl-described. i

In aitelephone exchange system, subscriljcrSl-lines, a common batteryjfor supplyving g-nu'nrentntlaiereto and a connective circuit 4-5; cem'piisingstheg following instrumentalities E an answferingtanda-calling plug, cord conductor's connecting the same and inductively divided; a pair of supervisory relays connectedzrespectively with the answering and and" a. generator, -a supervisory signal n a circuit controlled b each supervisory relay,- and nijeans'fforren enng said circuits oper-" atiye uthenihelplugsfare inserted, aringing and closed when .the'calling plug is'inserted, a disabling relay having contacts-controlling saidfringing relay "circuit and" itself con- 6,5; withdrawn, substantially as described.

thefcalling end'of .thecord, a ringing relay relay circuit alsocontrolled by said means,

i .4. Inimtelephbne.exchange system, a call ing anii"a' callectfsubscribers line, with a link i circuit having, switching terminals to 1 interconnect them; a ringing generator and means to connect it to "the called line only, 'zmagnetiomeansfor actuating said connecting-means, adapted to be controlled by the cal ingssubscriber, andother means independent thereof -for disabling the connect ing means, controlled by the called subscriber, substantially as described.

I In a telephone exchange system, a calling and a called line, and a link circuit for interconnecting them comprising an answeringira'nd a calling switch terminal and con- 30 'necting conductors inductively divided; a

supervisory relay connected with the answering end of-the link to be controlled by the calling subscriber, a second supervisory relay connected with thecalling end of the 35 link and controllable by the called subscriber, a link relay associated with the calling terminal and a suitable source or sources of current adapted to be connected thereby, means controlled by the answering supervisory relay as determined by the calling subscriber, for actuating the ringing relay, and means controlled by the calling supervisory relay as determined by the called subscriber for permitting or preventing the actuation of said ringing relay, substantially as described 6. In a telephone exchange system, subscribers lines, a common battery for supplying current thereto and a connective circuit comprising the following instrumentalities: answering and "calling switching terminals, link conductors connecting the same and inductively divided, a pair of relays connected respectively With the answering and calling end of the link, a ringing relay and a generator, supervising circuits controlled by each of said-relays, and means for rendering said circuits operative when the link terminals are connected, a ringing relay circuit controlled by said means and closed when the calling switching terminal is'connected, a disabling relay having contacts-controlling said ringing relay circuit and itself controlled by contacts in the calling' link relay, together with, controlling contacts for the ringing relay circuit in the answering link relay, and means whereby the disabling relay after being energized will remain energized until the calling link terminal is disconnected, substantially as described a 7. In a telephone exchange system, a calling and a called 'subscribers line, with a link circuit having switching terminals to 1.25 intercolmect them, a ninging generator and means to connect it to the called line only in making a connection, means adapted to intermittently actuate said generator connecting means, a device actuated in completing the connection for placing said generator connecting means under control of the calling subscriber, and mechanism controlled by the called subscriber and operable in the intervals of actuation only to dis able said generator connecting means, substantially as described.

8. In a telephone exchange system, a subscribers line and signal receiving apparatus, together with means at another station for making connection with said line; means under control of the calling subscriber for applying calling current at intervals to the called subscribers line after they are con-' nected, and other means controlled by the subscriber and operable in non-calling intervals only for disabling said means for l l s l applying the calling current, substantially as described.

9. In a telephone exchange system, subscribers lines, a common battery for said lines, a link circuit and calling means com.

prising the following instrumentalities: an answering and a calling switch terminal, a magnetically controlled ringing relay, a periodic circuit-closer for said relay, another relay associated. with the answering link terminal and controlled by a calling subscriber to open and close the circuit of the ringing relay, and still another relay associated With the calling link terminal and controllable by a called subscriber in the intervals of ringing, to disable or prevent the further actuation of said ringing relay, at will; all as and for the purpose'intended,

' substantially as described.

10. In a telephone exchange system, the

Y combination with a central exchange, of substations connected therewith through telephone lines, a cord circuitat the central exchange, a source of ringing current at the central exchange normallydlsconnected from the cord circuit, a relay controlling the connection of said source with the cord circuit, a second relay controlling the circuit for said first relay, and interrupter means in said circuit for periodically causing closure of said circuit to periodically cause action of the. first relay to connect the source with the cord circuit andwith a line connected therewith.

11. In a telephone exchange system, subscriber's" lines, a common battery for said lines, and a connecting cord circuit and calling means comprisingthe following instrumentalities: an answeringa-nd a calling plug,

a ringing relay, a periodic circuit closer connected to the wlndlngs of said relay on one side, a calling supervlsory relay connectedto the calling plug, normally closed contacts" on said relay connected to the ringing relay on its other side, a battery supply circuit for said supervisory relay contacts, a pair of contacts included in said battery circuit and directly opened and closed by the calling plug, when making and breaking connection with the wanted line. I

12. In a telephone exchange system, sub scribers lines, a common battery for said lines, and a connecting cord circuit and calling means comprising the following instrumentalit-ies: 'an answering ma a calling plug, a ringing relay, a periodic circuit closer connected to the windings of said relay on one side, a calling supervisory relay connected to the calling plug, normally closed contacts on said relay connected to the ringing relayon its other side, a battery supply circuit fol-said supervisory relay contacts, a pair of contacts included in said battery circuit and directly opened and closed by the calling plug, when making and breaking connection with the wanted line, together with a self-locking cut-ofi'.

relay having its windings connected to a normally open contact on said supervisory relay adapted to be closed on the battery supply circuit when the ringing relaywcircuit is disconnected therefrom, a pair of normally closed contacts in said cut-off relay connected serially in the circuit of the ringing relay, and a connection from the locking contactof said cut-ofi relay direct to the battery supply circuit leading through the plug controlvcircuits, whereby ringing will proceed forthwith when the calling plug is lifted from its seat and inserted in the wanted line jack, and when the subscriber answers the ringing relay will be cut oif, the locking relay energized, and ringing back thereby positively prevented by the continued energization of the locking relay until the calling plug shall have been removed from the wanted line jack and returned to its normal'or inoperative condition.

In testimony whereof I have affixed my signature in presence of two witnesses.

' EDWARD E. CLEMENT.

Witnesses: HUGH M. STERLING, JAMES H. MARR. 

